1. Field of the Invention
This invention relates to radio telephone apparatus which include a main station connected to a wire telephone line and a radio telephone set connected via a radio link with the main station and a method of controlling same, and more particularly to such apparatus having a function of holding telephone communication and a method of controlling same.
2. Description of the Related Art
There is a radio telephone apparatus which includes a main station connected with a wire telephone line and a radio telephone set connected via a radio link with the main station and which has a function of holding communication. The holding function is such that the user of the radio telephone set presses, for example, a holding button to hold telephone communication via the wire telephone line and to send a predetermined holding tone to the caller via the wire telephone line in order to have the caller wait for a while. The hold of the telephone communication is released by repressing the holding button or causing a subsidiary telephone set provided at the main station to go off-hook.
Assume that, for example, the user A of the radio telephone set presses the holding button to hold the telephone set in order to have the user C of a distant radio telephone set wait for a while and that the user A wants to reopen telephone communication with the user C using the radio telephone set. Under such condition, assume that another person B who does not know such situation picks up the handset of the subsidiary telephone set provided at the main station to go off-hook. This causes the hold state to be automatically release and causes the user B to abruptly talk to the user C, so that the user C would be confused while the user A would feel uncomfortable because the perfect stranger B joins the communication irrespective of the intention of the user A.
The radio link is left established between the main station and the radio telephone set under the hold condition. Thus if, for example, the user A of the radio telephone set presses the holding button to maintain the telephone set in a hold state and wants to reopen communication later via the subsidiary telephone set provided at the main station (he does not want to make telephone communication using the radio telephone set), power is consumed uselessly in order to maintain the unnecessary radio telephone line. Especially, if that the power source for the radio telephone set is a battery is considered, the consumption of the battery energy would become a big issue.